--[[ 50-gitsigns.lua — git diff signs plus hunk navigation/staging, via gitsigns.nvim.

Signs render by default in the always-on sign column; changed lines and their line numbers
are highlighted too (linehl/numhl).

Keymaps are buffer-local (set in on_attach):
`]c`/`[c` navigate hunks (falling through to Vim's builtin diff-mode nav when 'diff' is set)
`<Leader>h…` stage/reset/preview/blame, and `ih` is a hunk text object.

lualine reads the diff counts from gitsigns (see 50-color.lua).
]]

local gitsigns = require("gitsigns")

-- Jump to the next/prev hunk, falling through to builtin ]c/[c when in diff mode.
local function nav_hunk(direction)
	if vim.wo.diff then
		vim.cmd.normal({ direction == "next" and "]c" or "[c", bang = true })
	else
		gitsigns.nav_hunk(direction)
	end
end

-- Stage/reset the visually-selected range of lines.
local function stage_selection()
	gitsigns.stage_hunk({ vim.fn.line("."), vim.fn.line("v") })
end
local function reset_selection()
	gitsigns.reset_hunk({ vim.fn.line("."), vim.fn.line("v") })
end

local function blame_line()
	gitsigns.blame_line({ full = true })
end

-- Buffer-local gitsigns keymaps; passed as `on_attach`.
local function set_keymaps(bufnr)
	local function map(mode, lhs, rhs, desc)
		vim.keymap.set(mode, lhs, rhs, { buffer = bufnr, desc = desc })
	end

	-- Hunk navigation.
	map("n", "]c", function()
		nav_hunk("next")
	end, "Next git hunk")
	map("n", "[c", function()
		nav_hunk("prev")
	end, "Previous git hunk")

	-- Staging / resetting. `stage_hunk` toggles, so it also unstages a staged hunk.
	map("n", "<Leader>hs", gitsigns.stage_hunk, "Stage/unstage hunk")
	map("n", "<Leader>hr", gitsigns.reset_hunk, "Reset hunk")
	map("x", "<Leader>hs", stage_selection, "Stage selected hunk")
	map("x", "<Leader>hr", reset_selection, "Reset selected hunk")
	map("n", "<Leader>hS", gitsigns.stage_buffer, "Stage buffer")
	map("n", "<Leader>hR", gitsigns.reset_buffer, "Reset buffer")

	-- Inspecting.
	map("n", "<Leader>hp", gitsigns.preview_hunk, "Preview hunk")
	map("n", "<Leader>hb", blame_line, "Blame line")
	map("n", "<Leader>hd", gitsigns.diffthis, "Diff against index")

	-- Hunk text object.
	map({ "o", "x" }, "ih", gitsigns.select_hunk, "Inner git hunk")
end

gitsigns.setup({ on_attach = set_keymaps, linehl = true, numhl = true })